HID: add driver for the Logitech Flight System G940

Implements a new USB-HID for Force Feedback based on the normal
Logitech Force Feedback code and FF-Memless.

Currently only supports the FF_CONSTANT effect although the joystick
appears to support additional non-standard ones.

Signed-off-by: Gary Stein <LordCnidarian@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 176 insertions, 0 deletions

diff --git a/drivers/hid/hid-lg3ff.c b/drivers/hid/hid-lg3ff.c
new file mode 100644
index 0000000..4002832
--- /dev/null
+++ b/drivers/hid/hid-lg3ff.c
@@ -0,0 +1,176 @@
+/*
+ *  Force feedback support for Logitech Flight System G940
+ *
+ *  Copyright (c) 2009 Gary Stein <LordCnidarian@gmail.com>
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+
+#include <linux/input.h>
+#include <linux/usb.h>
+#include <linux/hid.h>
+
+#include "usbhid/usbhid.h"
+#include "hid-lg.h"
+
+/*
+ * G940 Theory of Operation (from experimentation)
+ *
+ * There are 63 fields (only 3 of them currently used)
+ * 0 - seems to be command field
+ * 1 - 30 deal with the x axis
+ * 31 -60 deal with the y axis
+ *
+ * Field 1 is x axis constant force
+ * Field 31 is y axis constant force
+ *
+ * other interesting fields 1,2,3,4 on x axis
+ * (same for 31,32,33,34 on y axis)
+ *
+ * 0 0 127 127 makes the joystick autocenter hard
+ *
+ * 127 0 127 127 makes the joystick loose on the right,
+ * but stops all movemnt left
+ *
+ * -127 0 -127 -127 makes the joystick loose on the left,
+ * but stops all movement right
+ *
+ * 0 0 -127 -127 makes the joystick rattle very hard
+ *
+ * I'm sure these are effects that I don't know enough about them
+ */
+
+struct lg3ff_device {
+	struct hid_report *report;
+};
+
+static int hid_lg3ff_play(struct input_dev *dev, void *data,
+			 struct ff_effect *effect)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
+	int x, y;
+
+/*
+ * Maxusage should always be 63 (maximum fields)
+ * likely a better way to ensure this data is clean
+ */
+	memset(report->field[0]->value, 0, sizeof(__s32)*report->field[0]->maxusage);
+
+	switch (effect->type) {
+	case FF_CONSTANT:
+/*
+ * Already clamped in ff_memless
+ * 0 is center (different then other logitech)
+ */
+		x = effect->u.ramp.start_level;
+		y = effect->u.ramp.end_level;
+
+		/* send command byte */
+		report->field[0]->value[0] = 0x51;
+
+/*
+ * Sign backwards from other Force3d pro
+ * which get recast here in two's complement 8 bits
+ */
+		report->field[0]->value[1] = (unsigned char)(-x);
+		report->field[0]->value[31] = (unsigned char)(-y);
+
+		usbhid_submit_report(hid, report, USB_DIR_OUT);
+		break;
+	}
+	return 0;
+}
+static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
+
+/*
+ * Auto Centering probed from device
+ * NOTE: deadman's switch on G940 must be covered
+ * for effects to work
+ */
+	report->field[0]->value[0] = 0x51;
+	report->field[0]->value[1] = 0x00;
+	report->field[0]->value[2] = 0x00;
+	report->field[0]->value[3] = 0x7F;
+	report->field[0]->value[4] = 0x7F;
+	report->field[0]->value[31] = 0x00;
+	report->field[0]->value[32] = 0x00;
+	report->field[0]->value[33] = 0x7F;
+	report->field[0]->value[34] = 0x7F;
+
+	usbhid_submit_report(hid, report, USB_DIR_OUT);
+}
+
+
+static const signed short ff3_joystick_ac[] = {
+	FF_CONSTANT,
+	FF_AUTOCENTER,
+	-1
+};
+
+int lg3ff_init(struct hid_device *hid)
+{
+	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
+	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct input_dev *dev = hidinput->input;
+	struct hid_report *report;
+	struct hid_field *field;
+	const signed short *ff_bits = ff3_joystick_ac;
+	int error;
+	int i;
+
+	/* Find the report to use */
+	if (list_empty(report_list)) {
+		err_hid("No output report found");
+		return -1;
+	}
+
+	/* Check that the report looks ok */
+	report = list_entry(report_list->next, struct hid_report, list);
+	if (!report) {
+		err_hid("NULL output report");
+		return -1;
+	}
+
+	field = report->field[0];
+	if (!field) {
+		err_hid("NULL field");
+		return -1;
+	}
+
+	/* Assume single fixed device G940 */
+	for (i = 0; ff_bits[i] >= 0; i++)
+		set_bit(ff_bits[i], dev->ffbit);
+
+	error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);
+	if (error)
+		return error;
+
+	if (test_bit(FF_AUTOCENTER, dev->ffbit))
+		dev->ff->set_autocenter = hid_lg3ff_set_autocenter;
+
+	dev_info(&hid->dev, "Force feedback for Logitech Flight System G940 by "
+			"Gary Stein <LordCnidarian@gmail.com>\n");
+	return 0;
+}
+